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ROBEH E. .ROGERS AND JAMES BLACK, OF PHILADELPHIA, 'PENN- SYLVANIA.

Letters .Patent No. 65,280, dated M'ay 28. 1867.

IMPROVEMENT IN STEAM GENERATORS.

TO ALL WI-IOM IT MAY CONUERN:

Be it known that We, ROBERT E. ROGERS and JAMES'BLACK, both ofthe city of Philadelphia, in the Statev of Pennsylvania, have invented certain new and useful Improvements in Steam Boilers; and we do hereby declaro that the following is a full, clear, and exact description of the construction and operation of the same, reference being had to the annexed drawings, forming part hereof, and to the letters of reference marked thereon, in which drawings v Figure 1 is a'front view of the boiler with the enlargement at its upper end, showing also the circulating tubes, (a portion of the boiler and of the tubes being cut away to show the inside of the boiler;) also the firegrates; also a vertical section ofthe fire-chamber in which the boiler is suspended.

Figure 2 `is a vertical section of the boiler, showing the curved circulating tubes and enlargements of the boiler at both top and bottom similar to the enlargement at top shown in iig. 1. l

Figure 3 is a vertical section of the boiler without enlargement at either end, showing the curved or bowed tubes for the circulation of thewater, and also showing screw-nuts lplaced either on the inside or both inside and outside of the boiler for the purpose of securing the tubes B to the shell ofthe boiler.

The improvements herein described are modifications of the steam boiler for which Letters Patent were granted to ns, the said R. E. ROGERS and J. BLACK, January 19, 1864; reissued December 19, 1865.

To enable others skilled in the art to make and use said `modifications of our original boiler, we will proceed to describe their construction and mode of operation.

A is 'the boiler having a bevelled enlargement, a, of its upper portion; B are tubes for the circulation of the water. Letters Patent were granted to the undersigned, June l2, 1866, describing external tubes on the vbody of the boiler. The tubes herein described are straight, except at their extreme ends where they are bent;

being straight, it has been found that their alternate expansion and contraction cause a direct thrust calculated to disturb theirjointsof insertion into the boiler. In order to obviate any injury to theirjoints of attachment these tubes are more ror less bowed or curved along their entire length. They are connected at bottom with the body of the boiler A directly and at top with the bevelled enlargement a, as shown in fig. 1. The circulating tubos B are commonly attached to the shell of the boiler by elbows and nipples, or by riveting. In place of this, however, they may be attached by means of screw-nuts with washers. These nuts being shown in iig. 3,'at N and N', or by slightly tapering the ends of the tubes B and applying the screw-nut on the inside only, as at M, iig. 3. C is a steam space inthe boiler A above the Water-line W. This space may or may not be connected with a supplemental chamber or steam-drum. in the ordinary manner of connecting steam-drums with boilers. E are rc-grates; D is the lire-chamber, which may be of masonry or of iron, or itmay be a steam-jacket. In

thischalnber the boiler A is shown to be suspended and wholly enclosed. This we prefer, but it is evident that` to gain good results the extreme upper portion constituting for the most part the steam space C of the boiler, need not be so enclosed, and in this-case the products of combustion are carried oil` laterally by a lue or pipe leading from the upper end of the Jdre-chamber. Instead of attaching the tubes B at bottom directly to the bottom ofthe boiler, as shown in iig. 1, the boiler maybe enlarged at bottom as at top, and the bowed or curved tubes B for thc circulation of the water may be attached at both bottom and top, as shown in iig. 2. We prefer the arrangement, as shown in iig. 1, as giving afreer exposure of the tubes to the heated products of combustion.

The advantages of our improvements are: First, by constructing the boiler with the bevelled expansion or expansions, the tubes can be attached thereto Without abruptly bending their ends, but by giving to the tubes a gentle curvature or bow-shape along their length, as shown in the three iigures. lSecond, by giving to thetubcs thc curved or bowed form described, they can expand and contract by changes of temperature without injuring or disturbing their joints of attachment to the boiler.' The water circulates through them more freely` than where there are short turns at theirv ends, sediment is less liable to lodge in them. and they are more easily cleaned and repaired.

It is evident that the degree of bevel given to the enlargement or enlargements of the boiler may vary according to the curvature intended to be given to the tubes B, and also that the area of the bevelled surface or surfaces may vary according to the number of tubes B intended to be inserted in them.

Having thusdescribed our invention, we claim, and desire to secure by Letters Patent- 1. The bevelied enlargement a of the boiler, in combination with the curved or bowed tubes B for the circulation of the wetensnd tubes being eittached at their upper ends to said enlargement a, and at their lower ends directly to the body ofthe boiler, in the manner and for the purpose substantially as shown and described.

2. The construction of the tubes B with a. continuous curve from one connection to the other of boiler,

substantially as herein set forth. l

3. The screw`11ut,in combination with the outside circulating tubes and shell of the boiler, one et each end, substantially as herein set forth.-

R. E. ROGERS,

JAMES BLACK.

Witnesses:

J. E. SHAW, Geo. E. BUCKLEY. 

